The UN's emergency relief co-ordinator, John Holmes, has described the refugee camps in Darfur as militarised.

Mr Holmes told the BBC that some of the 1.2 million refugees are impatient, politicised, and armed.

He said having thousands of disaffected men cooped up in camps in which weapons were available, was dangerous.

He believes the situation in the camps is bound to lead to clashes, and reflects the fact that there is no peace settlement in place for Darfur.

With Sudanese forces circling the camps the situation is potentially explosive.

"If you have large numbers of people in camps, you have the government of Sudan's military presence in the area, there are bound to be clashes from time to time, and the politicisation and militarisation on the ground in the camps is a fact of life you can't ignore," Mr Holmes said.

His remarks come at a particularly sensitive moment.

The UN Secretary-General, Ban Ki-moon, is due to travel to Sudan next week, the first time the current head of the UN has visited the troubled region.

The Sudanese government has in the past accused the Darfur rebels of using the sprawling UN camps.

While Mr Holmes denied the camps had become rebel bases, his remarks are likely to be favourably received in Khartoum.